The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 04, 2000
Filed:
May. 01, 1998
Jonathan William Byrn, Kasson, MN (US);
Chad B McBride, Rochester, MN (US);
Brian Andrew Schuelke, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A frequency shift detection circuit for detecting a frequency shift between a first signal and a second signal includes two or more delay circuits coupled to one another in series and two or more comparison logic circuits. The first delay circuit in the series receives one of the first and second signals and produces a delayed replica. Each of the other delay circuits receives the delayed replica produced by the previous delay circuit in the series and produces a further delayed replica. Thus, the signal produced by each delay circuit is delayed from the original signal by a different amount. Each comparison logic circuit receives one of the delayed replicas and receives the other one of the first and second signals, i.e., the one that is not received by the delay circuits. In response, the comparison logic circuit produces a frequency shift detection signal when it detects a phase difference between that other one of said first and second signals and the delayed replica. By selecting or tapping one of the outputs of the comparison logic circuits, a user can select the detection granularity.